This is a question with no answer, but I'll throw in my 2 anyway.
Hitting a baseball with some sort of relative skill(no, not just getting lucky and tipping it)is probably the single hardest thing to do in sport.
It is precisely because as some have said the ability to do it is to a large degree something that you need to be "born with".
Believe me, standing in a batting box with somebody 60 feet away throwing a hard ball in your direction at ninety miles per hour would make most people soil their shorts, not even taking into consideration making some sort of meaningful contact. If you've never done it, TV does not do it justice, it can be a very frightening experience with somebody throwing 90+ mph.
Distance running at a high school level can be achieved with sheer determination and hard work for most individuals. I don't think I could say the same thing for playing baseball at a high school level. I did play high school baseball, and I am now in my 40's and have run times that would have easily put me on the varsity even at this advanced age. However, you can go practice in a batting cage forever and never "get it". It's simply the gift of "hand/eye" coordination.
This does not mean that baseball players are great "athletes", it just means that they can hit a baseball. Ironically, it has little to do with "athletic" ability.